Halomonas radicis sp. nov., isolated from Arthrocnemum macrostachyum growing in the Odiel marshes(Spain) and emended descriptions of Halomonas xinjiangensis and Halomonas zincidurans

Strain EAR18(T) was isolated as an endophyte from the roots of a halophyte plant, Arthrocnemum macrostachyum, growing in the Odiel marshes (Huelva, Spain). Cells of strain EAR18T were Gram- stain-negative, motile, non-spore-forming aerobic rods. It grew optimally on tryptic soy agar supplemented with 2.5% NaCl (w/v), at pH 7 and 30 degrees C for 48 h. It tolerated NaCl from 0 to 25 % (w/v). It presented Q9 as the major quinone and C-19:0 cyclo omega 8c, summed feature 8 (C-18:1 omega 7c and/or C:(1.8:1)omega bc) and C-16:0 as the predominant fatty acids. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and four unidentified phospholipids. The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that strain EAR18(T) formed a well-supported clade with species Halomonas zincidurans B6(T) and Halomonas xinjiangensis TRM 0175(T) (similarities of 98.3 and 96.1% respectively). Furthermore, digital DNA-DNA hybridization analysis resulted in values of 20.4 % with H. xinjiangensis TRM 0175(T) and 35.50 % with H. zincidurans B6(T), and ANIb/ANIm results in values of 73.8 %/84.2 % with H. xinjiangensis TRM 0175(T) and 86.8 %/89.4% with H. zincidurans B6(T). Based on phylogeny and differential phenotypic properties in comparison with its closest related species, strain EAR18(T) is suggested to represent a new species in the genus Halomonas, for which the name Halomonas radicis sp. nov. is proposed. The type strain is EAR18(T) (=CECT 9077(T)=LMG 29859(T)). The whole genome was sequenced, and it had a total length of 4.6 Mbp and a G+C content of 64.9 mol%.